Examples of the known refrigerant evaporator include a configuration in which first and second evaporation portions are arranged in line in a flowing direction of the cooling target fluid. The first and second evaporation portions each includes a core portion having multiple stacked tubes, and a pair of tank units connected to both end portions of the multiple tubes. One of the tank units of each evaporation portion is coupled to each other through a pair of communicating portions (for example, see Patent Document 1).
In the refrigerant evaporator disclosed in Patent Document 1, when a refrigerant flows from a core portion of the first evaporation portion to a core portion of the second evaporation portion through one of the tank units of each evaporation portion and the pair of communicating portions that couples the tank units, the flow of the refrigerant is switched in the width direction (tube stacking direction, or right-left direction) of the core portions. In other words, the refrigerant evaporator is configured to make a refrigerant flow from one side of the core portion of the first evaporation portion in the width direction to an opposite side of the core portion of the second evaporation portion in the width direction through one of the pair of communicating portions, and make a refrigerant flow from another side of the core portion of the first evaporation portion in the width direction to an opposite side of the core portion of the second evaporation portion in the width direction through the other communication portion.
Also, in the refrigerant evaporator of Patent Document 1, the pair of communicating portions is an intersecting communicating portion in which the refrigerant flows intersect with each other leftward and rightward. The intersecting communicating portion is disposed in the tank unit of the first evaporation portion or the second evaporation portion, or in an intermediate tank provided between the tank unit of the first evaporation portion and the tank unit of the second evaporation portion.